import gevent
import random

def f1():
    for i in range(1, 6):
        print('f1', i)
        gevent.sleep(20)


def f2():
    for i in range(6, 11):
        print('f2', i)
        gevent.sleep(0)


# t1 = gevent.spawn(f1)
# t2 = gevent.spawn(f2)
for i in range(0,5):
    gevent.spawn(f1())